The present invention concerns a highly active and highly selective aromatization catalyst that contains platinum, a type L zeolite, and at least one promoter selected from the group consisting of iron, cobalt, titanium, and the rare earth metals.
Catalytic reforming is a well-known process that is used to raise the octane rating of a naphtha. The reactions that occur during reforming include: dehydrogenation of cyclohexanes, dehydroisomerization of alkylcyclopentanes, dehydrocyclization of acyclic hydrocarbons, dealkylation of alkylbenzenes, isomerization of paraffins, and hydrocracking of paraffins. The hydrocracking reaction should be suppressed because that reaction lowers the yield of hydrogen and lowers the yield of liquid products.
Reforming catalysts must be selective for dehydrocyclization in order to produce high yields of liquid product and low yields of light gases. These catalysts should possess good activity so that low temperatures can be used in the reformer.
While most reforming catalysts contain platinum on an alumina support, large-pore zeolites have been proposed as catalyst supports. These large-pore zeolites have pores large enough for hydrocarbons in the gasoline boiling range to pass through.